Analysis Command

Both MPM and FEA calculations can do 2D or axisymmetric calculations. MPM can additionally do 3D calculations. You pick the type of analysis to run with an analysis command. In scripted commands, the format is

Analysis (number or name)

In XML files it is

<Analysis>(number)</Analysis>

The possible analysis types, by number or name, to use in above commands, are:

• 0 = "Plane Strain" for a 2D plane strain FEA analysis
• 1 = "Plane stress" for a 2D plane stress FEA analysis
• 2 = "Axisymmetric" for an Axisymmetric FEA analysis
• 10 = "Plane Strain MPM" for 2D plane strain dynamic MPM analysis
• 11 = "Plane Stress MPM" or 2D plane stress dynamic MPM analysis
• 12 = "3D MPM" or 3D dynamic MPM analysis
• 13 = "Axisymmetric MPM" for axisymmetric dynamic MPM analysis

When using analysis name in scripts, it must exactly match the quoted text above (case insensitive). When writing XML files, the entry must be by number only.

Tracking Particle Spin

OSParticulas has an option to track particle spin that can improve results in problems with rotation (especially when using a PIC method). For scripted input files, simply add "+PS" to the option name (and must be by name and not number):

• "Plane Strain MPM+PS" for 2D plane strain dynamic MPM analysis with particle spin.
• "Plane Stress MPM+PS" or 2D plane stress dynamic MPM analysis with particle spin.
• "3D MPM+PS" or 3D dynamic MPM analysis with particle spin.
• "Axisymmetric MPM+PS" for axisymmetric dynamic MPM analysis with particle spin.

In XML files, pick the MPM number from above and then add the following command to the <MPMHeader>

<TrackParticleSpin/>

Notes

• The first three (0,1,2) are for FEA calculations only, while the rest (10,11,12,13) are for MPM calculations only.
• In axisymmetric analyses, the x, y, z, directions become R, Z, and θ directions. If any commands do not mention use of R and Z, they may still work or you can use x and y to mean the same thing. When visualizing results, most labels are changed to reflect R, Z, and θ coordinates. The implementation of axisymmetric MPM is described in a paper by Nairn and Guilkey.
• One (and only one) Analysis command is required in every input file and it should be near the beginning, because many other commands depend on whether or not the commands are for FEA or for MPM analysis.